you should not skip a major release.
Update to 3.0.4.6 now so you have the best basis for 3.0.5

Why did you not update to 3.0.4.x in the past?
If you are concerned with problems in the first release of a major version step you could wait for a 3.0.5.1 but if the build is as good as I aspect it to be it might take some time until a fix release .1 is released

OT:
Is it good idea to let the updater to reconfigure services during update? I did some tweaking in mysql, apache etc settings in /etc manually. Will updater respect my settings, or will it rewrite that completely to default? thanks

Due to some time issues I was not able (and am not yet either) to be as involved in the development of 3.0.5 as I would have liked.
Till is the maintainer and the only one who can give you a correct estimate on the release.

Beta means that there are no features missing. Everything needs work smoothly.
If no errors will be found the beta could even be released as the as the stable version but...
Because no one wants to run a beta version in production it takes some time and testers to check everything for issues.

There is no release date yet for ISPConfig 3.0.5. We are curently testing the beta and fix the remaining issues that are listed in the bugtracker, when the issues are fixed, then I will release a 3.0.5 RC.

ISPConfig versions get released when we feel that they are stable enough for production use, it will help nobody if we will release unfinished software just because we set a release date on day X.

If you want to use 3.0.5 right now, the download it from svn 3.0.5 stable branch and install it, this would be the same as if we said release date is today. You get the software will all issues that are not marked as closed in the bugtracker at the given date.